- From: Olaf Hartig <hartig@informatik.hu-berlin.de>
- Date: Mon, 25 Oct 2010 08:41:16 +0200
- To: public-xg-prov@w3.org
Hey, On Sunday 24 October 2010 15:50:28 Paul Groth wrote: > Hi Olaf, > > Thanks for the comments. Really good. Some replies in-line > [...] > > 1.) Regarding Sec.2, third bullet point "Specify how to embed provenance > > in document with RDFa ..." and regarding point (1) in Deliverable D4: > > * Why is this only about embedding provenance in HTML documents? > > Provenance of data retrieved from the Web (e.g. from a Linked Data URI > > look-up interface, or from a SPARQL endpoint) is equally important I > > would say. > > It shouldn't be just about RDFa. This is probably not clear enough. We > want to be able to retrieve provenance of any web-resource, through the > mechanisms you mention URI look-up interface or a sparql endpoint. Some comments regarding the last sentence: * Here you speak about "retrieve provenance" but the part of the draft chapter I referred to with my question are about embedding (at least, that's what I thought it was about). * (related to the previous point) It was not my intention to mention Linked Data URI look-up interface and SPARQL endpoints as mechanisms to retrieve provenance. Instead, I wanted to suggest the following: if the WG specifies how to embed provenance into HTML documents then it should also specify how to embed provenance into the RDF graphs retrieved from a Linked Data interface and into the result set retrieved from a SPARQL endpoint. * You speak about "provenance of any web-resource". I still struggle to see how Web resources, in general, have provenance. To me provenance is associated primarily with specific representations of Web resources that we retrieve from the Web. > > 2.) Regarding Deliverable D4: What does "(3) how to query provenance > > through a SPARQL endpoint" mean? What do you have in mind here? > > This would specify about retrieving provenance for a resource using > sparql. So given a resource, how would you write a sparql query to > retrieve that resource provenance. Do we talk about a SPARQL endpoint that exposes a dataset which explicitly contains provenance information here? In this case it shouldn't be too difficult to write such queries; you only have to know which provenance vocabulary is being used to represent provenance information in the dataset. However, another, related question: what do you understand as "a resource" here? If it is a Web resource again (i.e. something that can be requested directly using a URL), then what are examples for provenance of it? > [...] > > 4.) Regarding Sec.2 "The Working group will keep this two-pronged > > approach for the mapping to RDF: a simple vocabulary allowing provenance > > to be asserted easily, and an ontology that extends the vocabulary with > > permitted inference." - Why? I'm not familiar with the OPM ontology and > > what it provides in addition to OPMV, but why shouldn't it be possible > > to satisfy both requirements (ease of asserting provenance and > > permitting inferences) with a single vocabulary? I would say that it > > requires at least some investigation whether an easy to use vocabulary > > can or can not provide for all kinds of inferencing possible with OWL. > > For instance, our Provenance Vocabulary provides support for inferring > > additional statements using some of the constructs available in OWL2. > > So the OPM ontology (OPMO) supports inferences about provenance using > OWL. But there were some things that were easier if you took some > "features" out of the simpler vocabulary. Jun can explain this better. > But one example was the notion of being able to express edges as simple > rdf edges instead of using reification. Or for example, inferring > account membership. Ah, I see the difference. Thanks for clarification. Greetings, Olaf
Received on Monday, 25 October 2010 06:41:54 UTC